Procedure for controlling the set-up of calls with transmission channel requirement of different network terminations

ABSTRACT

In order to be able to control the setting up of telecommunication connections efficiently and reliably in telecommunication subsystems serving as local message transmission loops of telecomunication systems and having network terminations which differ with regard to the transmission channel requirements, a first network termination specifies explicitly, for example in the form of a parameter, the requested transmission channel desired by it in a connection, set-up message of the network termination to the remote station in the telecommunication subsystem.

In telecommunication systems having a message transmission route betweena message source and a message sink, transmitting and receiving devicesare used for message processing and transmission, in which

1) the message processing and message transmission can be carried out ina preferred transmission direction (simplex operation) or in bothtransmission directions (duplex operation),

2) the message processing is analogue or digital,

3) the message transmission is wire-based over the trunk transmissionroute, or is carried out wire-free on the basis of various messagetransmission methods FDMA (Frequency Division Multiple Access), TDMA(Time Division Multiple Access) and/or CDMA (Code Division MuiltipleAccess)—for example in accordance with radio standards such as DECT,GSM, WACS or PACS, IS-54, PHS, PDC, etc. [cf. IEEE CommicationsMagazine, January 1995, pages 50 to 57; D. D. Falconer et al.: “TimeDivision Multiple Access Methods for Wireless Personal Communications”].

“Message” is a generic term which covers both the useful content(information) and the physical representation (signal). Despite amessage having the same useful content—that is to say the sameinformation—different signal forms may occur. Thus, for example, amessage relating to an object may be transmitted

(1) in the form of an image,

(2) as the spoken word,

(3) as the written word,

(4) as an encrypted word or image.

The type of transmission in accordance with (1) . . . (3) is in thiscase normally characterized by continuous (analogue) signals, while inthe case of the transmission type according to (4), the signals arenormally discontinuous (for example pulses, digital signals).

On the basis of this general definition of a message system, theinvention relates to a method for controlling the setting up oftelecommunication connections in telecommunication subsystems serving aslocal message transmission loops of telecommnication systems and havingnetwork terminations which differ with regard to the transmissionchannel requirements, in particular “ISDN/PSTN⇄DECT-specific RLL/WLL”systems, in accordance with the preamble of Patent Claim 1.

Using as references the documents “Nachrichtentechnik Elektronik[Telecommunications Electronics], Berlin 45 (1995) Issue 1, pages 21 to23 and Issue 3, pages 29 and 30” as well as IEE Colloquium 1993, 173;(1993), pages 29/1-29/7; W. Hing, F. Halsall: “Cordless access to theISDN basic rate service”, and on the basis of a DECT/ISDN IntermediateSystems DIIS according to ETSI publication prETS 300xxx, Version 1.09,Jul. 31, 1996, FIG. 1 shows an “ISDN⇄DECT-specific RLL/WLL”Telecommunication System IDRW-TS (Integrated Services DigitalNetwork⇄Radio in the Local Loop/Wireless in the Local Loop) with an ISDNtelecommunication subsystem [cf. document “Nachrichtentechnik Elektronik[Telecommunications Electronics], Berlin 41-43, Parts: 1 to 10, Part 1:(1991) Issue 3, pages 99 to 102; Part 2: (1991) Issue 4, pages 138 to143; Part 3: (1991) Issue 5, pages 179 to 182 and Issue 6, pages 219 to220; Part 4: (1991) Issue 6, pages 220 to 222 and (1992) Issue 1, pages19 to 20; Part 5: (1992) Issue 2, pages 59 to 62 and (1992) Issue 3,pages 99 to 102; Part 6: (1992) Issue 4, pages 150 to 153; Part 7:(1992) Issue 6, pages 238 to 241; Part 8: (1993) Issue 1, pages 29 to33; Part 9: (1993) Issue 2, pages 95 to 97 and (1993) Issue 3, pages 129to 135; Part 10: (1993) Issue 4, pages 187 to 190;”] and a DECT-specificRLL/WLL Telecommunication Subsystem RW-TSS.

The DECT/ISDN Intermediate System DIIS and the RLL/WLL telecommunicationsubsystem RW-TSS are in this case preferably based on a DECT/GAP systemDGS [Digital Enhanced (previously: European) Cordless Telecommunication;cf. (1): Nachrichtentechnik Elektronik 42 (1992) January/February No. 1,Berlin, DE; U. Pilger “Struktur des DECT-Standards” [Structure of theDECT standard], pages 23 to 29 in conjunction with the ETSI publicationETS 300175-1 . . . 9, October 1992; (2): Telecom Report 16 (1993), No.1, J. H. Koch: “Digitaler Komfort für schnurloseTelekommunikation—DECT-Standard eröffnet neue Nutzungsgebiete” [Digitalconvenience for cordless telecommunication—DECT standard opens up newfields of applications], pages 26 and 27; (3): tec 2/93—Das technischeMagazin von Ascom “Wege zur universellen mobilen Telekommunikation” [Thetechnical magazine from Ascom “Means for universal mobiletelecommunication”], pages 35 to 42; (4): Philips TelecommunicationReview Vol. 49, No. 3, September 1991, R. J. Mulder: “DECT, a universalcordless access system”; (5): WO 93/21719 (FIGS. 1 to 3 with associateddescription)]. The GAP standard (Generic Access Profile) is a subset ofthe DECT standard which has the task of ensuring interoperability of theDECT radio interface for telephone applications (cf. ETSI publicationprETS 300444, April 1995).

The DECT/ISDN Intermediate system DIIS and the RLL/WLL telecommunicationsubsystem RW-TSS can alternatively be based on a GSM system (GroupeSpéciale Mobile or Global System for Mobile Communication; cf.Inoformatik Spektrum 14 (1991) June, No. 3, Berlin, DE; A. Mann: “DerGSM-Standard—Grundlage für digitale europäische Mobilfunknetze” [The GSMstandard—Basis for digital European mobile radio networks], pages 137 to152). Instead of this, it is also possible in the context of a hybridtelecommuication system for the ISDN telecommunication subsystem I-TSSto be designed as a GSM system or PSTN system (Public SwitchedTelecommunication Network).

Furthermore, further possible ways for realizing the DECT/ISDNIntermediate System DIIS, the RLL/WLL telecommunication subsystem RW-TSSor the ISDN telecommunication subsystem I-TTS include the systemsmentioned in the introduction as well as future systems which are basedon the known multiple access methods FDMA, TDMA, CDMA (FrequencyDivision Multiple Access, Time Division Multiple Access, Code DivisionMultiple Access) and hybrid multiple access methods formed from them.

The use of radio channels (for example DECT channels) in classicalcable-based telecommunication systems, such as ISDN, is becomingincreasingly important, particularly against the background of futurealternative network operators without their own complete cable network.

Thus, for example in the case of the RLL/WLL telecommunication subsystemRW-TSS, the wire-free connection technology RLL/WLL (Radio in the LocalLoop/Wireless in the Local Loop) for example including the DECT systemDS, ISDN services should be made available to the ISDN subscriber onstandard ISDN interfaces (cf. FIG. 1).

In the “ISDN⇄DECT-specific RLL/WLL” telecommunication system IDRW-TSaccording to FIG. 1, a telecommunication subscriber (user) TCU(Tele-Communication User) with terminal TE (Terminal Endpoint; TerminalEquipment), is included in the ISDN world, with the services availablein it, for example via a standardized S interface (S-BUS), the DECT/ISDNIntermediate System DIIS, which is designed as a local messagetransmission loop—is preferably DECT-specific and is contained in theRLL/WLL telecommunication subsystem RW-TSS—(first telecommunicationsubsystem), a further standardized S interface (S-BUS), a NetworkTermination NT and a standardized U interface of the ISDNtelecommunication subsystem I-TTS (second telecommnication subsystem).

The first telecommunication subsystem DIIS essentially comprises twotelecommunication interfaces, a first telecommunication interface DIFS(DECT Intermediate Fixed System) and a second telecommunicationinterface DIPS (DECT Intermediate Portable System), which are connectedto one another without wires, for example via a DECT radio interface.Because of the quasi-position-based first telecommunication interfaceDIIS, the first telecommunication subsystem DIIS forms the local messagetransmission loop defined above in this context. The firsttelecommuication interface DIFS contains a Radio Fixed Part RFP, anInterWorking Unit IWU1 and an INterface Circuit INC1 for the Sinterface. The second telecommunication interface DIPS contains a RadioPortable Part RPP and an InterWorking Unit IWU2 and an INterface CircuitINC2 for the S interface. The radio fixed part RFP and the radioportable part RPP in this case form the known DECT/GAP system DGS.

Taking the “ISDN⇄DECT-specific RLL/WLL” telecommunication system IDRW-TSwith the RLL/WLL telecommunication subsystem RW-TSS according to FIG. 1as a departure point, FIG. 2 shows a typical RLL/WLL scenario. Thewire-free connection technology RLL/WLL (Radio in the LocalLoop/Wireless in the Local Loop) for example including a DECT system isintended to make ISDN/PSTN services available to an ISDN/PSTN subscriberon standard ISDN/PSTN interfaces in the present case. The use of radiochannels (for example DECT channels) in classical cable-basedtelecommunication systems, such as ISDN/PSTN, is becoming increasinglyimportant, particularly against the background of future alternativenetwork operators without their own complete cable network.

The RLL/WLL scenario illustrated comprises, for example, the currentlycommercially available Siemens DECT Link system Version 1 (DECT Link V1)and the DECT Link systems Versions 2 and 3 (DECT Link V2, DECT Link V3)which can be derived from Version 1 by further development.

A Radio Network Termination with an analogue a/b connection is employedin the abovementioned, known DECT Link V1 system. One refers to a radionetwork termination RNT-1 in this case. The radio network terminationRNT-1 has a radio connection to a radio base station RBS1 . . . RBS3,for example the radio base station RBS3. The radio network terminationRNT-1 requires a maximum of one user information channel (TrafficChannel). The data on this traffic channel are generally ADPCMvoice-encoded at 32 kbit/s. The consequence of using a voice encoder isthat maximum data rates (for example of modems or fax machines) of 9.6kbit/s can be transmitted only inadequately via a 32 kbit/s DECTchannel. Moreover, the 9.6 kbit/s can only be achieved under optimumconditions.

It is furthermore possible to employ a radio network termination with“n” analogue a/b connections. A radio network termination RNT-4 withfour a/b connections was introduced in the DECT Link system Version 2(DECT Link V2). The RNT-4 requires a maximum of up to four userinformation channels (Traffic Channels) simultaneously. In the case ofthe radio network termination RNT-4, these user information. channelswere generally ADPCM-encoded, as in the case of the radio networktermination RNT-1. In order, however, to relieve the load on the DECTradio interface, it is possible, in the case of the DECT Link V2, tooperate the individual connections for the radio network terminationRNT-4 via different radio base stations RBS (for examiple the threeradio base stations RBS1 . . . RBS3). In the case illustrated, the radionetwork termination RNT-4 is connected, for example, to the radio basestation RBS1. The setting up of connections is in this case carried outby a Radio Distribution Unit RDU. A base station control device RBC(Radio Base station Controller) is provided between the radiodistribution unit RDU and the individual radio base stations. The basestation control device RBC is a pure “layer 1” module. It demultiplexesthe data of the radio distribution unit and matches them to theinterface to the respective radio base station. The radio base stationtransmits the data via the DECT radio interface to the radio networktermination (RNT-4).

The transmission rate that is available in the abovementioned DECT Linksystems is inadequate for an ISDN subscriber connection. Specifically,64 kbit/s with defined bit error rates are required per B channel forISDN.

In order to be able to optimally utilize the DECT channel capacity, itis necessary to distinguish between voice transmission and datatransmission. More DECT channels must be made available for datatransmission than for voice transmission.

The 64 kbit/s LU7 service for data transmission via DECT is defined inthe ETSI publication prETS 300434-1; January 1996 (DECT and ISDN InterWorking For End System Configuration). The data rate is oriented towardsthe ISDN B channel.

The ETSI publication prETS 300xxx; Version 1.09; Jul. 31, 1996(DECT/ISDN Inter Working for Intermediate System Configuration)describes the transmission of an ISDN interface via the DECT radiochanmel. In this case, a conversion of the ISDN D channel protocol viathe IWU protocol layer (Inter Working Unit) to the DECT protocol takesplace in a Radio Fixed Part and a Radio Portable Part in theDECT-specific RLL/WLL system (cf. DE Patent Applications 19625142.7 and19625141.9). The protocol data are transmitted in the C plane e.g. inthe C_(f) signalling channel via the DECT radio channel. The ISDNconnection is subsequently made available again at an ISDN-specificradio network termination, designated as RNT_(i).

These considerations have led to the DECT Link system Version 3 (DECTLink V3). The DECT Link V3 system has, for example, a DECT-specificradio network termination RNT_(i) with ISDN capability for aterrestrially connectable ISDN terminal TE (Terminal Endpoint) and/or aterrestrially connectable ISDN Private Automatic Branch Exchange PABX aswell as a data service-supporting, DECT-specific radio networktermination RNT-n_(d) with e.g. “n=4” a/b connections for datatransmission for terrestrially connectable data terminals. The radionetwork terminations RNT_(i), RNT-n_(d) are connected via a DECT radiointerface, having a plurality of radio channels, for example to thethree radio base stations RBS1 . . . RBS3.

Consequently, in the case of the radio network termination RNT-n_(d),once again a maximum of four user information channels (TrafficChannels) would be simultaneously possible. In the case of the radionetwork termination RNT_(i), it would be two user information channels(2 B channels) and one signalling channel (D channel).

As in the case of the DECT Link V2 system, it is again possible in theDECT Link V3 system to operate the various user information andsignalling channels via different radio base stations RBS1 . . . RBS3for the purpose of uniform capacity utilization of the DECT radiochannel.

Unlike the DECT Link V2 system, two different DECT transmission paths(bearers) are supported in the DECT Link V3 system, the 32 kbit/sADPCM-encoded voice service and the 64 kbit/s LU7 data service. Incontrast to the voice service, the data service requires two DECT timeslots.

In the case of the radio network terminations RNT_(i), RNT-n_(d), adistinction is made between the transmission of voice data and, forexample, modem data, in order to be able to better utilize the DECTchannel capacity. For voice connections, in general only connectionswith 32 kbit/s ADPCM-encoded channels are set up. For datatransmissions, channels with the 64 kbit/s LU7 data service are set up.

In principle, the number of respective radio network terminationsRNT_(i), RNT-n_(d) and the number of radio base stations RBS1 . . . RBS3can be freely selected; it will, however, preferably depend on theinstallation location of the “ISDN/PSTN⇄DECT-specific RLL/WLL”telecommunication system (keyword: network planning).

The radio network terminations RNT-1, RNT-4, RNT_(i), RNT-n_(d) and theradio base stations RBS1 . . . RBS3 form the DECT-specific RLL/WLLtelecommunication subsystem RW-TSS and the RLL/WLL scenario. The RLL/WLLtelecommunication subsystem RW-TSS is connected, on the networktermination side, to the said cable-based terminals and, on the networkside, as already mentioned, via a base station control device RCB and aradio distribution unit RDU to the ISDN/PSTN telecommuication systemISDN, PSTN (ISDN/PSTN network). There is a system channel SYC on whichsystem messages SYM are transmitted, between the ISDN/PSTNtelecommuication system ISDN, PSTN and the radio distribution unit RDU.The system messages SYM in this case contain, for example, ISDNsignalling messages and/or ISDN/PSTN user messages. There are subsystemchannels SSC on which the system messages SYM and subsystem messages SSMare transmitted, between the radio base stations RBS1 . . . RBS3 and thebase station control device RBC, on the one hand, and between the radiobase stations RBS1 . . . RBS3 and the radio network terminations RNT-1,RNT-4, RNT_(i), RNT-n_(d), on the other hand. The subsystem channels SSCcontain, on the one hand, subsystem channels SSC_(nts) on the networktermination side, which correspond to the radio channels, and subsystemchannels SSC_(ns) on the network side.

An ISDN connection is made available to the subscriber by the radionetwork termination RNT_(i). For this purpose, the radio networktermination RNT_(i) can request either on the C plane a C_(f) channel(f=fast) for the transmission of signalling data or on the U plane auser data channel with a capacity of 32 kbit/s or 64 kbit/s via the DECTradio interface from the network side.

Four subscribers are respectively provided with one connection with datacapability by the radio network termination RNT-n_(d).

For this purpose, the radio network termination RNT-n_(d) can likewiserequest a user data channel with a capacity of 32 kbit/s or 64 kbit/svia the DECT radio interface from the network side.

A specific channel resource (first channel of the subsystem channels onthe network side) is necessary for routing the C_(f) channel on theterrestrial side (between radio base station and radio distributionunit). The number of first channels between the radio base station andthe radio distribution unit is preferably limited. In the present case,there are four first channels, for example.

A further—in the present case unlimited—channel resource is necessaryfor the routing of the user data channel on the terrestrial side(between radio base station and radio distribution unit).

For the transmission of theme chapels, a connection is set up via theDECT radio interface in the telecommunication subsystem, more preciselythe radio base station and the radio network termination, in each caseon the MAC protocol layer with a “B field set-up procedure for advancedconnections” (cf. ETSI Publication ETS 300175-3, October 1992, Chapter7.3, in particular is Chapter 7.3.3).

As a result of the restricted number of first channels, a radio basestation is not allowed to permit the setting up of more than four MACconnections to a respective C_(f) channel for signalling.

However, the DECT radio interface does permit the reception of a fifthset-up request for a MAC connection.

The problem therefore consists in the fact that

1) more channel resources (C_(f) channels) are available via the DECTradio interface than can be covered on the terrestrial side,

2) the user data channel of the radio network termination RNT-n_(d) withthe capacity of 32 kbit/s cannot be distinguished from the C_(f) channelusing the “B field set-up procedure for advanced connections”.

The user data channel of the radio network termination RNT_(i) with thecapacity of 32 kbit/s can be distinguished from the C_(f) channel of theradio network termination RNT_(i) using the transmission path parameter“LCN” (Logical Connection Number).

One suggested solution to the problem is based on the evaluation of thetransmission path parameter “LCN” and of the parameter “PMID” (PortableMAC IDentifier) of the MAC message “BEARER_REQUEST” (cf. ETSIPublication ETS 300175-3, October 1992, Chapter 7.3.3.2). Using theseparameters, the radio base station would enquire of the radiodistribution unit whether the requested channel is a C_(f) channel.

The radio distribution unit manages the request data and can thusunambiguously identify the requested channel using the parameters “PMID”and “LCN”.

This solution is impractical because the connection set-up times wouldbecome unacceptably long due to the telecommunication between radio basestation and radio distribution unit.

SUMMARY OF THE INVENTION

The object on which the invention is based consists in enabling thesetting up of telecomunication connections to be controlled efficientlyand reliably in telecommunication subsystems serving as local messagetransmission loops of telecommuication systems and having networkterminations which differ with regard to the transmission channelrequirements, in particular “ISDN/PSTN⇄DECT-specific RLL/WLL” systems.

The idea on which the invention is based consists in controlling thesetting up of telecommunication connections in telecommunicationsubsystems serving as local message transmission loops oftelecommunication systems and having network terminations which differwith regard to the transmission channel requirements, of the typementioned in the introduction, in such a way that a first networktermination specifies explicitly, for example in the form of aparameter, the requested transmission channel desired by it in aconnection set-up message of the network termination to the remotestation in the telecommunication subsystem.

As a result, the remote station can—particularly when the channelsrequested by the network terminations are identical with regard to thetransmission capacity—on the one hand distinguish between the networkterminations and, on the other hand, accordingly assign the respectivelyrequested channel to the network terminations.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present invention which are believed to be novel,are set forth with particularity in the appended claims. The invention,together with further objects and advantages, may best be understood byreference to the following description taken in conjunction with theaccompanying drawing, in which:

FIG. 1 depicts prior art related to the present invention;

FIG. 2 depicts the method of the present invention; and

FIG. 3 further depicts the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 3 uses a stimulus state diagram to show how it is possible tocontrol the respective setting up of telecommunication connectionsefficiently and reliably in telecommunication subsystems serving aslocal message transmission loops of telecommunication systems and havingnetwork terminations which differ with regard to the transmissionchannel requirements, in particular “ISDN/PSTN⇄DECT-specific RLL/WLL”systems.

The radio network termination RNT_(i) sends to the radio base stationRBS2 the connection set-up request after reception of a MAC message“CONNECTION_REQUEST” CRQ (cf. ETSI Publication ETS 300175-3, October1992, Chapter 8, 8.1, 8.1.1) with a first subsystem message SSM1,corresponding to the MAC message “BEARER_REQUEST” (cf. ETSI PublicationETS 300175-3, October 1992, Chapter 7.3.3.2), via the DECT radiointerface. This subsystem message SSM1 contains a first parameter“SERVICE TYPE” having a first parameter value “C_(f)-CHANNEL ONLY”.

The radio base station RBS2 recognizes from the first parameter valuethat the radio network termination RNT, would like to set up theconnection, and it recognizes in particular that on the terrestrialside, a first channel of the subsystem channels SSC_(ns) on the networkside is required for connecting the signalling channels to the systemchannels SYC and/or for the routing of the signalling channels of thetelecommunication subsystems RW-TSS to the telecommnication systemsISDN, PSTN (a restricted channel resource).

If the radio base station RBS2 cannot make the required channel resourceavailable because all of the first channels are busy, the connectionrequest is rejected in that the radio base station RBS2 transmits asecond subsystem message SSM2, corresponding to the MAC message“RELEASE” (cf. ETSI Publication ETS 300175-3, October 1992, Chapter7.3.3.10) to the radio network termination RNT_(i). The second subsystemmessage SSM2 indicates the reason for rejecting the connection by meansof a second parameter “RELEASE REASON” contained in the subsystemmessage SSM2 and having a second parameter value “RADIO BASE STATIONBUSY”.

The radio network termination RNT_(i) thereupon repeats theabove-described connection request procedure with a different radio basestation, for example the radio base station RBS3.

Since the radio base station RBS3 can make the required channel resourceavailable because at least one first channel is free, the connectionrequest is accepted in that the radio base station RBS3 transmits athird subsystem message SSM3, corresponding to the MAC message“BEARER_CONFIRM” (cf. ETSI Publication ETS 300175-3, October 1992,Chapter 7.3.3.3), to the radio network termination RNT_(i). Stillfurther messages are then transmitted between the radio base stationRBS3 and the radio network termination RNT_(i), until the radio basestation RBS3 sends a MAC message “CONNECTION_INDICATE” CIN (cf. ETSIPublication ETS 300175-3, October 1992, Chapter 8, 8.1, 8.1.1) to theradio distribution unit. Afterwards, further messages are once againtransmitted between the radio base station RBS3 and the radio networktermination RNT_(i) until the radio network termination RNT_(i) sends aMAC message “CONNECTION_CONFIRM” CCF (cf. ETSI Publication ETS 300175-3,October 1992, Chapter 8, 8.1, 8.1.1) to the subscriber station. Theinvention is not limited to the particular details of the methoddepicted and other modifications and applications are contemplated.Certain other changes may be made in the above described method withoutdeparting from the true spirit and scope of the invention hereininvolved. It is intended, therefore, that the subject matter in theabove depiction shall be interpreted as illustrative and not in alimiting sense.

What is claimed is:
 1. A method for controlling setting up oftelecommunication connections in telecommunication subsystems serving aslocal message transmission loops of telecommunication systems and havingnetwork terminations which differ with regard to the transmissionchannel requirements, comprising the steps of: a) transmitting systemmessages on system channels in the telecommunication systems; b)providing the telecommunication subsystems with a plurality of subsystemchannels for transmitting subsystem messages and the system messages; c)providing the telecommunication subsystems with telecommunicationinterfaces, which are connected via network termination-specificsubsystem channels to second telecommunication interfaces and/or thirdtelecommunication interfaces, which are structured as networkterminations, and also via network-specific subsystem channels to thesystem channels; d) incorporating the telecommunication subsystems intothe telecommunication systems via the telecommunication interfaces; e)providing the network termination-specific subsystem channels withsignalling channels and user data channels; f) transmitting the messagesfrom and to the second telecommunication interfaces via the signallingchannels and/or the user data channels, and transmitting the messagesfrom and to the third telecommunication interfaces via the user datachannels; g) transmitting first subsystem messages having firstparameters from the second telecommunication interfaces and/or the thirdtelecommunication interfaces to the first telecommunication interfaces,for connection setting up; h) transmitting the first parameters of thefirst subsystem messages having first parameter values containingcontents “SIGNALLING CHANNEL ONLY” from the second telecommunicationinterfaces to primary telecommunication interfaces of the firsttelecommunication interfaces; i) connecting the signalling channels tofirst channels of the network-specific subsystem channels for connectingthe signalling channels to the system channels and/or for routing of thesignalling channels of the telecommunication subsystem to thetelecommunication systems.
 2. The method according to claim 1, wherein anumber of first channels is limited.
 3. The method according to claim 2,wherein as a response t the first subsystem messages having the firstparameters and the first parameter values, second subsystem messageshaving second parameters and second parameter values containing contents“PRIMARY TELECOMMUNICATION INTERFACE BUSY” are transmitted from theprimary telecommunication interfaces to the second telecommunicationinterfaces when the first channels are all busy.
 4. The method accordingto claim 3, wherein the first parameters of the first subsystem messageshaving the first parameter values are transmitted from the secondtelecommunication interfaces to secondary telecommunication interfacesof the first telecommunication interfaces when the secondtelecommunication interfaces receive the second subsystem messageshaving the second parameters and the second parameter values.
 5. Themethod according to claim 4, wherein the first parameters of the firstsubsystem messages having the first parameter values are transmittedfrom the second telecommunication interfaces to the firsttelecommunication interfaces until the second telecommunicationinterfaces receive third subsystem messages having the first parametersand the first parameter values.
 6. The method according to claim 1,wherein the telecommunication system is an ISDN system and PSTN system.7. The method according to claim 1, wherein the telecommunicationsubsystem is a DECT system.
 8. The method according to claim 1, whereinthe telecommunication subsystem is a GSM system.
 9. The method accordingto claim 1, wherein the telecommunication subsystem is one of a PHSsystem, a WACS system or a PACS system.
 10. The method according toclaim 1, wherein the telecommunication subsystem is one of an “IS-54”system or a PDC system.
 11. The method according to claim 1, wherein thetelecommunication subsystem is one of a CDMA system, a TDMA system, anFDMA system or a, with regard to the said transmission standards hybridsystem.
 12. The method according to claim 1, wherein the firsttelecommunication interface is a DECT/GAP-specific radio base station,the second telecommunication interface is a DECT-specific radio networktermination with ISDN capability, and the third telecommunicationinterface is a DECT-specific radio network termination which isstructured for n-fold data transmission.
 13. The method according toclaim 7, wherein the first subsystem messages are DECT-specific “MACprotocol layer” messages “BEARER_REQUEST”, the first parameters areDECT-specific “MAC protocol layer” parameters “SERVICE TYPE”, the firstparameter values having the contents “SIGNALLING CHANNEL ONLY” areDECT-specific “MAC protocol layer” parameter values “C_(f)-CHANNELONLY”, the second subsystem messages are DECT-specific “MAC protocollayer” messages “RELEASE”, the second parameters are DECT-specific “MACprotocol layer” parameters “RELEASE REASON”, the second parameter valueshaving the contents “PRIMARY TELECOMMUNICATION INTERFACE BUSY” areDECT-specific “MAC protocol layer” parameter values “RADIO BASE STATIONBUSY”, and the third subsystem messages are DECT-specific “MAC protocollayer” messages “BEARER_CONFIRM”.
 14. The method according to claim 4,wherein the telecommunication subsystem is a DECT system.